Conventional known tanning processes consist of a series of operations aimed at transforming raw natural leather skin of animals under the chemical action of tannins or of organic or inorganic agents, especially chromium salts zirconium salts, aluminum salts, syntans, synthetic multifunctional organic polymers, aldehydes, aldehyde derivatives, all of which can be applied to collagen singly or more commonly in combination. The purpose of tanning processes is to improve the skin texture and to give the leather obtained mechanical strength properties, particularly heat resistance, suitable for the subsequent manufacturing operations. Existing tanning processes allow this optimization leather properties but are unfavorable to the environment due to the use of difficult to recycle or eliminable metals. In addition, the use of metals sometimes generates allergenic reactions to the user.
In order to overcome the above drawbacks, the present skin tanning method uses liquid smoke as a tanning agent so as to obtain good quality, cost efficient, improved texture quality, nontoxic, organic and rot resistant leather products. The liquid smoke is used in place of chemically derived aldehydes, which are commonly used in the tanning process and known to introduce toxicity into the animal skin.
Numerous innovations for tanning animal skin have been provided as described below. Even though these innovations may be suitable for the specific purposes to which they address, they differ significantly from the present invention, however.
U.S. Pat. No. 2,103,138, to Becker et al., teaches a process for production of uniform artificial gut from animal fibrous starting material such as hide or sinews, which is neither over nor under-hardened, may be obtained by converting the said starting materials into a swollen condition, shredding the swollen material, extruding the resulting swollen fibrous masses from nozzles containing annular orifices and hardening the resulting artificial gut by treating the artificial gut with hardening liquids containing formaldehyde and iodine consuming substances occurring in the distillates of cellulose containing substances, however Becker et al. does not teach a liquid smoke tanning method that uses liquid smoke as a tanning agent to crosslink collagen proteins on an animal skin during the tanning process of the present invention and several other advantages and improvement of the present invention.
U.S. Pat. No. 3,894,158 to Miller, teaches a process for the manufacture of edible collagen casing by incorporating liquid smoke into an extrusion mass of acid-swollen collagen, extruding said liquid-smoke containing acid swollen collagen extrusion mass into the shape of a casing and drying the resultant edible collagen casing. Miller does not, however, teach use of liquid smoke as a tanning agent to crosslink collagen proteins on an animal skin and several other advantages and improvement of the present invention.
U.S. Pat. No. 4,917,924 to Huang et al., teaches a processable food package comprising an indicia-containing casing filled with processable food to which the color indicia is transferred during processing, an edible food product with the color indicia on its outer surface as for example processed frankfurter with grill marks, and a method for making the indicia-containing processed food product. Other additives with special properties may be included, for example liquid smoke to impart color, flavor and odor to the indicia.
U.S. Pat. No. 7,754,258 to Morgan et al., teaches an extruded collagen film, made from an extrudable gel, wherein said film has a collagen content that consists of porcine collagen, essentially of sow collagen. The gel may also include coagulating agents such as minor amounts of glutaraldehyde, glyoxal, liquid smoke or multivalent cation (such as aluminum) which are effective to cross-link the collagen film and thereby increase its strength. However, Morgan et al. does not teach the process of the present invention for tanning an animal skin such as a hide or fur by using liquid smoke as a tanning agent and several other advantages and improvement of the present invention.
U.S. Pub. No. 20,090,162,502 to Bueker et al., teaches a process for producing a collagen-concentrate-containing food casing that includes producing an aqueous collagen mass; concentrating the aqueous collagen mass; admixing the concentrate with dilute acid to obtain a extrudable or castable collagen mass; coextruding the collagen mass to from a casing and solidifying the casing by treatment with liquid smoke or other chemical crosslinkers. Bueker et al. does not, however, teach the process of the present invention for tanning an animal skin by using liquid smoke as a tanning agent and several other advantages and improvement of the present invention.
It is apparent now that numerous innovations for treating an animal skin or collagen have been provided in the prior art that are adequate for various purposes. Furthermore, even though these innovations may be suitable for the specific purposes to which they address, accordingly, they would not be suitable for the purposes of the present invention as heretofore described. Thus a liquid smoke tanning method that uses liquid smoke as a tanning agent to crosslink collagen proteins on an animal skin during the tanning process so as to produce a stable, rot resistant, nontoxic and organic leather material is needed.